Performance Evaluation of Fuel Indirect Cooling Based Thermal Management System Using Liquid Metal for Hydrocarbon-Fueled Scramjet

Hydrocarbon-fueled scramjet is one of the most promising air-breathing propulsion systems for hypersonic flight, but the wall thermal protection issue strictly limits its maximum flight Mach number. This study presents a fuel indirect cooling based thermal management system (TMS) scheme, in which liquid metal acts as wall coolant and fuel serves as the final heat sink of heat dissipation. Results indicate that fuel indirect cooling based TMS has an excellent performance on combustor wall protection. It is meaningful to maintain a high inlet temperature of wall cooling channel (Tlm1) to avoid pinch point issue and obtain a compact size for bypass heat-exchanger. Benefiting from large heat transfer coefficient of liquid metal, the highest temperature of combustor wall is no more than 1325 K at the heat flux density with maximum value of nearly 5.5 MW/m2. In addition, in the view of combustor wall thermal protection, the upper limit of flight Mach number for hydrocarbon-fueled scramjet can reach 9 theoretically, when the fuel indirect cooling based TMS with Tlm1 of 1023 K is employed. This research provides an innovative solution in the wall thermal protection and heat dissipation utilization for hydrocarbon-fueled scramjets at high Mach numbers